docs: def v_lift_valve_Crane(rho, D1=None, D2=None, style='swing check angled'):
      r'''Calculates the approximate minimum velocity required to lift the disk 
      or other controlling element of a check valve to a fully open, stable,
      position according to the Crane method [1]_.
      
      .. math::        
          v_{min} = N\cdot \text{m/s} \cdot \sqrt{\frac{\text{kg/m}^3}{\rho}}
      
      .. math::
          v_{min} = N\beta^2 \cdot \text{m/s} \cdot \sqrt{\frac{\text{kg/m}^3}{\rho}}
          
      See the notes for the definition of values of N and which check valves use 
      which formulas.
  
      Parameters
      ----------
      rho : float
          Density of the fluid [kg/m^3]
      D1 : float, optional
          Diameter of the valve bore (must be equal to or smaller than 
          `D2`), [m]
      D2 : float, optional
          Diameter of the pipe attached to the valve, [m]
      style : str
          The type of valve; one of ['swing check angled', 'swing check straight',
          'swing check UL', 'lift check straight', 'lift check angled', 
          'tilting check 5°', 'tilting check 15°', 'stop check globe 1', 
          'stop check angle 1', 'stop check globe 2',  'stop check angle 2', 
          'stop check globe 3', 'stop check angle 3', 'foot valve poppet disc', 
          'foot valve hinged disc'], [-]
  
      Returns
      -------
      v_min : float
          Approximate minimum velocity required to keep the disc fully lifted,
          preventing chattering and wear [m/s]
  
      Notes
      -----
      This equation is not dimensionless.
  
      +--------------------------+-----+------+
      | Name/string              | N   | Full |
      +==========================+=====+======+
      | 'swing check angled'     | 45  | No   |
      +--------------------------+-----+------+
      | 'swing check straight'   | 75  | No   |
      +--------------------------+-----+------+
      | 'swing check UL'         | 120 | No   |
      +--------------------------+-----+------+
      | 'lift check straight'    | 50  | Yes  |
      +--------------------------+-----+------+
      | 'lift check angled'      | 170 | Yes  |
      +--------------------------+-----+------+
      | 'tilting check 5°'       | 100 | No   |
      +--------------------------+-----+------+
      | 'tilting check 15°'      | 40  | No   |
      +--------------------------+-----+------+
      | 'stop check globe 1'     | 70  | Yes  |
      +--------------------------+-----+------+
      | 'stop check angle 1'     | 95  | Yes  |
      +--------------------------+-----+------+
      | 'stop check globe 2'     | 75  | Yes  |
      +--------------------------+-----+------+
      | 'stop check angle 2'     | 75  | Yes  |
      +--------------------------+-----+------+
      | 'stop check globe 3'     | 170 | Yes  |
      +--------------------------+-----+------+
      | 'stop check angle 3'     | 170 | Yes  |
      +--------------------------+-----+------+
      | 'foot valve poppet disc' | 20  | No   |
      +--------------------------+-----+------+
      | 'foot valve hinged disc' | 45  | No   |
      +--------------------------+-----+------+
  
      Examples
      --------
      >>> v_lift_valve_Crane(rho=998.2, D1=0.0627, D2=0.0779, style='lift check straight')
      1.0252301935349286
      
      References
      ----------
      .. [1] Crane Co. Flow of Fluids Through Valves, Fittings, and Pipe. Crane,
         2009.
      '''
      specific_volume = 1./rho
      if D1 is not None and D2 is not None:
          beta = D1/D2
          beta2 = beta*beta
      if style == 'swing check angled':
          return 45.0*specific_volume**0.5
      elif style == 'swing check straight':
          return 75.0*specific_volume**0.5
      elif style == 'swing check UL':
          return 120.0*specific_volume**0.5
      elif style == 'lift check straight':
          return 50.0*beta2*specific_volume**0.5
      elif style == 'lift check angled':
          return 170.0*beta2*specific_volume**0.5
      elif style == 'tilting check 5°':
          return 100.0*specific_volume**0.5
      elif style == 'tilting check 15°':
          return 40.0*specific_volume**0.5
      elif style == 'stop check globe 1':
          return 70.0*beta2*specific_volume**0.5
      elif style == 'stop check angle 1':
          return 95.0*beta2*specific_volume**0.5
      elif style in ('stop check globe 2', 'stop check angle 2'):
          return 75.0*beta2*specific_volume**0.5
      elif style in ('stop check globe 3', 'stop check angle 3'):
          return 170.0*beta2*specific_volume**0.5
      elif style == 'foot valve poppet disc':
          return 20.0*specific_volume**0.5
      elif style == 'foot valve hinged disc':
          return 45.0*specific_volume**0.5